Spitzer Observations of the Oldest White Dwarfs in the Solar Neighborhood

Understand

We present Spitzer 5-15 micron spectroscopy of one cool white dwarf and 3.6-8 micron photometry of 51 cool white dwarfs with T_eff < 6000 K.

• The majority of our targets have accurate BVRIJHK photometry and trigonometric parallax measurements available, which enables us to perform a detailed model atmosphere analysis using their optical, near- and mid-infrared photometry with state- of-the-art model atmospheres.
• We demonstrate that the optical and infrared spectral energy distributions of cool white dwarfs are well reproduced by our grid of models.
• Our best fit models are consistent with the observations within 5% in all filters except the IRAC 8 micron band, which has the lowest signal- to-noise ratio photometry.